Problem: Evaluate the following expression when $y = 5$ and $x = 4$. $4$ $y$ $ + 7$ $x$ $ - 3$
Answer: Substitute $5$ for ${y}$ and $4$ for ${x}$ $ = 4{(5)} + 7{(4)} - 3 $ $ = 20 + 28 - 3 $ $ = 45$